These are better copies than the leopard safari fakes for example, where the easiest way to spot them would be by looking at the clip. The adjustable clip would just be on the right side instead of the left side.

The CDG fake can be spotted by looking at the tags, stitching and the odd looking fit. The upper part is much to high.

I guess anyone who has ever seen a real Supreme cap can spot these from a mile away, so don't worry.